A primary coil with more turns and a secondary coil with less turns are mounted on the same core. The voltage ratio of input to output is equal to the ratio of coil turns, while the energy remains unchanged.

Therefore, the secondary coil generates high current under low voltage. For the induction heater, the bearing is a short-circuit single-turn secondary coil, which passes through a large current at a lower AC voltage, thus generating a great deal of heat.

The heater itself and the yoke remain at room temperature. Because this heating method can induce current, the bearing will be magnetized. It is important to ensure that the bearings will be de-magnetized in the future and that the manufacturers of copper-casting heating rings will not absorb metal magnetic debris during operation.

FAG induction heater has automatic degaussing function. It uses the eddy current produced by metal in alternating magnetic field to heat itself. It is usually used in metal heat treatment and so on.

The principle is that when a thicker metal is in an alternating magnetic field, it will generate current due to electromagnetic induction. When a thick metal produces current, the current will form a spiral flow path inside the metal, so that the heat generated by the current flow will be absorbed by the metal itself, which will lead to the rapid heating of the metal.